ESSENTIAL FATTY ACIDS
Information from NRC and Canine and Feline Nutrition and Small Animal Clinical Nutrition
The essential fatty acids are polyunsaturated fatty acids. These essential fatty acids (EFA) include two families: Omega 3 Fatty Acids and Omega 6 Fatty Acids. As their levels increase, the requirements for antioxidants (mainly vitamin E), also increase.
Common Omega 6 Fatty Acids
- Linoleic Acid (LA)
- Arachidonic Acid (ARA)
Common Omega 3 Fatty Acids
- Alpha-linolenic acid (ALA)
- Eicosapentaenoic Acid (EPA)
- Docosahexaenoic Acid (DHA)
Omega 6: Linoleic Acid and Arachidonic Acid
While there are other forms, LA and ARA are the essential fatty acids we look at the most.
Linoleic Acid is converted to Arachidonic Acid. There is a recommended allowance for LA, but not for ARA in adult dogs because they can convert LA to ARA. However, ARA is still a high quality, bioavailable omega 6 source for adult dogs. Puppies, kittens, and adult cats require ARA. The metabolic process to convert LA to ARA requires additional resources.
Arachidonic Acid is needed for healthy gut and skin barriers. It is needed for a natural and healing inflammatory response. Without it, the body cannot reach the inflammatory status required for healing.
Linoleic acid can be found in the fat and skin of duck, chicken. and pork. However, it can also be found in plant oils such as safflower oil. LA should be specifically added when there is not enough ARA and LA combined. LA is not needed if there is enough ARA.
Arachidonic Acid is found in the fat of animals as well, especially duck fat. It is rich in organ meats and egg yolks. Because ARA is much more bioavailable compared to LA, dogs need much less of it by weight. Even though there is no ARA recommended allowance for adult dogs, one can be estimated. This is useful because it prevents the excessive addition of LA sources when they are not needed.
For example, a 65 lb dog has a daily requirement for roughly 4.5 g of omega 6 as LA. However, because ARA is more bioavailable, they may need just 10% of what is required of LA when omega 6 is supplied as ARA. In other words, supplying this same dog with just 0.75 g of ARA could more than meet their omega 6 requirement independent of LA intake.
High amounts of omega 6 increase the antioxidant requirements. Suboptimal intake can interfere with skin and gut barrier health.
Omega 3: Alpha-Linolenic Acid, EPA, and DHA
While there are other forms, ALA, EPA, and DHA are the most common forms to work with on a dietary basis. Ultimately, DHA is responsible for the resolution of inflammation, neurological functions, and much more.
ALA is poorly converted to DHA by Dogs and is not converted by felines. ALA, when converted, becomes DHA. However, canines are not very good at this process. Therefore, when sources of EPA and DHA cannot be fed, ALA should be used as the last resort. Given the low potency, it should not be granted much weight when considering the omega 6:3 ratio. ALA is rich in oils such as flaxseed. Providing ALA when there are already abundant amounts of EPA and DHA merely increases the pet’s antioxidant requirements.
EPA can be found in marine sources such as sardine, mackerel, and fish body oils. It is found naturally with DHA. The recommended allowance includes a combination of EPA and DHA. There isn’t a requirement for each specifically spelled out because conversion is unknown. High amounts of EPA interfere with omega 6 metabolism. High doses of fish body oil are not without risks and side effects.
DHA is found in the same fish as EPA. It is also found in small amounts in the dark meat of chicken. Brain is a unique source of DHA that is useful for pets who cannot have marine sources. However, its purchase is not always safe or legal.
Meeting the EPA and DHA requirement abundantly means the ALA requirement can often be ignored.
High amounts of omega 3 have a blood thinning affect, may interfere with Omega 6 metabolism, and increase the antioxidant requirements. Suboptimal intake may contribute to poor skin and coat health and overall inflammatory disturbances.
Myth: ALA should be used to balance the fats within a diet.
It is commonly advised to add ALA sources, such as nuts and seeds (or their oils), to diets rich in LA (poultry or pork inclusive diets). However, if you are feeding an animal based diets rich in bioavailable fatty acids (Omega 3 as DHA and Omega 6 as ARA), you likely do not need to add additional plant oils to the formulation for proactive formulations. Inclusion of these oils drives up the antioxidant requirements. However, in the rare chance you are feeding a plant based diet, LA:ALA ratio becomes important. The LA:ALA ratio is typically unimportant in the context of typical whole food, animal based diets. Always analyze the diets you are feeding. Including whole plant matter foods will provide natural amounts of prebiotic fiber, phytonutrients, and ALA. Therapeutic formulations require more careful EFA balancing.
Myth: Omega 6 (LA) should be added to beef based diets.
LA is converted to ARA. Ultimately, ARA is what is required for healthy skin, GI tract, and more. If ARA and LA is short, then LA or ARA may be added to the diet in the form of oils or additional animal fats. A proper diet analysis should be done. Adding additional LA when enough ARA is present increases the antioxidant requirements. Therefore, seeds and seed oils are typically not needed when feeding an animal based diet already rich in ARA.
Myth: Omega 6 is inflammatory.
This is more of an oversimplification. Omega 6, specifically arachidonic acid, allows the body to have a healthy, healing inflammatory response to injury, illness, or even regular physiological functions (such as reproduction). If inflammation is a problem, one should look for an underlying cause. Removing or interfering with the metabolism of omega 6 is removing an essential nutrient. It is a pharmacological approach that is only sometimes therapeutically appropriate.
The full course has several lessons on fatty acid metabolism, formulation, and sources. You can also visit Feed Thy Dog’s guide to fat here.